<?php

    // Iterative solution
    function factorial($number){
        $result = 1;
        for($i=1; $i <= $number ; $i++){
            $result *=$i;
        }
        return $result;
    }

    // Iterative using a reverse loop
    function factorialReverse($number){
        $result = 1;
        while($number !=1){
            $result *= $number;
            $number--;
        }
        return $result;
    }

    // Recursive solution
    function factorialRecursive($number){
        if($number ==1){
            return 1;
        }
        else{
            return $number *factorialRecursive($number-1);
        }
    }

?>